This invention is a fluid depth regulator or penstock which will provide improved, easier control of water and fluid levels in rice fields, oil well run off pits or any other application where fluids need to be maintained at a pre-determined level, raised or lowered, between two or more liquid holding areas.
This penstock can be used to control the water level held by dikes, small levees and similar structures. It greatly improves present methods of fluid level control by reducting manhours, energy expenditure and replacement costs. More importantly, the risk of catastropic fluid loss is eliminated by the unique method involved in blocking and passing the flow of water within the throat of the penstock mechanism, together with the seepage prevention techniques employed.
Specifically, within the area of rice field culture, the cultivating of rice requires a capability for, during the growth cycle of the rice, flooding a rice field to a controllable depth, raising and lowering the water levels periodically within the rice field, and draining the rice field to a very low level. In addition, it is common in the rice fields of Southern Louisiana to raise crayfish as a second crop within a rice field. Crayfish cultivation requires additional water level controls during the growth and harvesting cycles of the crayfish, and normally requires considerably deeper water than the cultivation of rice.
Prior art methods of maintaining and establishing water levels within a system of levees or dikes for rice production and crayfish production are both time consuming and costly. In one case, the method consists of cutting a gap within a levee, installing a plastic apron within that gap and covering the sides of the apron with dirt to prevent seepage or washing out of the cut. In order to raise the depth of water in the rice paddy, the plastic apron must be raised and dirt or some object placed underneath. Lowering the water depths would require removing the dirt beneath the plastic apron and deepening the the gap. This procedure of adjusting the depth often requires the work of two men at a time. The life expectancy of the plastic apron is only one to two years, depending on the type of material used in making it.
An alternate method of control is to cut an opening in a levee with a shovel allowing the water to flow through freely, and then closing the gap in the levee by filling in the hole. This method is a cheaper expedient in comparison to using the classic sliding gate penstocks that have been shown in the prior art.
Water control through these penstocks is established by raising and lowering a sliding gate. It is obvious that if the gate is raised, water is flowing through the bottom of the penstock, and unless the gate is shut, the field being drained will be drained completely dry. A constant water level cannot be maintained by this method. As a result, rice farmers have habitually used the levee-cut method, which has the advantage that if the cut is left open and erosion is restrained, water level only goes down to the level of the cut made in the levee. Therefore, an accident or jamming of the flow control means will not result in a drying out of the rice field.
A final method in common use in rice fields is the installation of flexible plastic pipe through a levee with a three- or four-foot flexible end extending into the lower of the two paddies. A post with block and tackle or similar mechanism is then used to enable a man to raise and lower the lower end. As will be obvious, this pipe then works as an inverted siphon and establishes a fluid level based on the height to which the long end has been raised. Again, this is in the nature of a temporary field expedient. The piping mechanism has a lifetime of from one to two years in actual use, and, of course, the mechanism must be constantly monitored as a break in the rope or a failure in the mechanism will result again in a complete draining of the upper field.
Similar requirements for maintaining a constant level of water in a pool or pond or for separating and establishing the flow off of an upper layer of a liquid while resisting the flow or drainage of a lower layer of liquid are encountered in oil well pits where oil and water must be separated, or in similar separation ponds encountered in environmental control applications or in chemical factories. Again, the liquid control means requires that a cut to a certain depth or an opening to a certain depth be made in the levy or wall forming the pond. Liquid above this depth then flows off into a second pond or second area. Liquid below that depth is maintained in the first pond.